Note: Descriptions are shown in the official language in which they were submitted.
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Patent Application
of
Jason Thomas
Krzysztof Korcz
for
HINGED SPLIT BUSHING
FIELD OF THE INVENTION
[0001]The present invention relates generally to split bushings for electrical
conduits. More particularly, the present invention relates to hinged split
bushings for electrical conduits including an integral tightening mechanism.
BACKGROUND OF THE INVENTION
[0002]Bushings are known in the art. Bushings exist to cover the open end of
an electrical conduit tube in order to protect the wires from becoming frayed
or
damaged from rubbing against the exposed edge of the conduit. This
concern is particularly acute when dealing with thin-walled metal conduits
that
present a thin, almost blade-like, edge and conduits that are cut to size
which
may present sharp, serrated, or rough areas that can damage the wires.
Where possible, bushings are used during insulation. A solid ring of an
appropriate size for the conduit circumference is fitted onto the end of the
conduit to cover the exposed edge and present a smooth inner wall and dull
lip for receiving wires and cables threaded through the conduit. This
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arrangement prevents the end of the conduit from presenting a cutting hazard
to the wires and cables.
[0003] Situations arise when a bushing is needed for a conduit through which
cables have already been run. For example, situations such as when a
bushing was forgotten, or when a previously installed bushing breaks or
needs to be removed. The prior art developed what are known as "split
bushings" for these occurrences. Split bushings are bushings that have a cut
or slit in their sidewall. The slit allows the bushing ends on each side of
the
slit to be pulled apart from one another wide enough to allow wires and cables
to pass into the bushing's interior. The split bushing having the cables
threaded therethrough, is then secured to the conduit end akin to a solid
bushing and thereafter operates to protect the wires in the same manner.
[0004] As recognized by the present inventors, a drawback with prior art
bushings, and split bushings in particular, is the inability to use one
bushing
for varying sized conduits and varying conduit types. Another drawback
recognized by the present inventor is the inability to tighten or lock a split
bushing in place without using external or other materials apart from the
bushing. Yet another drawback recognized by the present inventor is the
expense incurred to mold many prior art plastic split bushings.
[0005] The foregoing highlights some of the problems with conventional spit
bushings as recognized by the present inventors. Furthermore, the foregoing
highlights the present inventors' recognition of a long-felt, yet unresolved
need
in the art for a split bushing capable of being permanently installed. In
addition, the foregoing highlights the inventors' recognition of a need in the
art
for a split bushing capable of use with varying conduit types. Finally, the
foregoing highlights the present inventors' recognition of the need for a cost
effective plastic molded split bushing that overcomes the problems in the art.
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SUMMARY OF THE INVENTION
[0006]Various embodiments of the present invention overcome various of the
aforementioned and other disadvantages associated with prior art split
bushings and offers new advantages as well.
[0007]According to one aspect of various embodiments of the present
invention, there is provided a split bushing including a hinge. In accordance
with this aspect, some embodiments of the invention include a "living hinge."
A presently preferred living hinge comprises a thinned area in the bushing
opposite the sidewall split. More preferably, the bushing comprises plastic
and the living hinge is a thin area of plastic configured to allow the bushing
to
bend in an open position. An advantageous feature of this embodiment is the
ability to mold the split bushing including a living hinge as one continuous
part.
[0008]According to another aspect of various embodiments of the present
invention, there is provided a split bushing having a tightening mechanism. In
accordance with this aspect, some embodiments of the invention include a
means for connecting each of the ends of the bushing at the slit. A presently
preferred embodiment of the connecting means comprises a male tongue with
locking ridges on a first end and a female receiving orifice on the second
end.
More preferably, the male ends ridges are configured to provide a "one-way"
matting with the female end.
[0009]As will be appreciated, similar to zip ties, the male end's ridges, or
teeth, are profiled with an inclined surface to cam into the catch and then be
blocked from being pulled out in the opposite direction by a vertical face.
Thus, the male end may be threaded further into the catch and reduce the
circumference of the bushing and tighten the bushing in place. Likewise, the
length of the tongue allows for the bushing to be placed around conduits that
have a circumference larger than the circumference of the bushing in the fully
closed position. An advantageous feature of this embodiment is the ability to
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mold the split bushing including the tightening mechanism as one continuous
part.
[0010]The invention as described and claimed herein should become evident
to a person of ordinary skill in the art given the following enabling
description
and drawings. The drawings are for illustration purposes only and are not
drawn to scale unless otherwise indicated. The drawings are not intended to
limit the scope of the invention. The following enabling disclosure is
directed
to one of ordinary skill in the art and presupposes that those aspects of the
invention within the ability of the ordinarily skilled artisan are understood
and
appreciated.
[0011]As used in this application, the terms "front," "rear," "upper,"
"lower,"
"upwardly," "downwardly," and other orientational descriptors are intended to
facilitate the description of the exemplary embodiment of the present
invention, and are not intended to limit the structure of the exemplary
embodiment of the present invention to any particular position or orientation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012]Various aspects and advantageous features of embodiments of the
present invention will become more apparent to those of ordinary skill when
described in the detailed description of a preferred embodiment and reference
to the accompany drawing wherein:
[0013]FIG. 1 is a perspective view of a prior art split bushing being deployed
on a conduit,
[0014]FIG. 2 is a right, perspective view of a split bushing in the closed
position according to an embodiment of the invention.
[0015]FIG. 3 is a top view of the split bushing of FIG. 2.
[0016]FIG. 4 is a right, perspective view of a split bushing in a partially
closed
position according to an embodiment of the invention.
[0017]FIG. 5 is a top view of the split bushing of FIG. 4.
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[0018] FIG. 6 is a top view of a split bushing in the open position according
to
an embodiment of the invention.
[0019] FIG. 7 is a bottom view of the split bushing of FIG. 6.
[0020] FIG. 8 is an elevated, right perspective view of the split bushing of
FIG.
6.
[0021] FIG. 9 is a bottom, right perspective view of the split bushing of
FIG.6.
[0022] FIG. 10 is a bottom, left perspective view of the split bushing of FIG
6.
[0023]Throughout the drawings, like reference numerals will be understood to
refer to like parts, components and structures.
DETAILED DESCRIPTION
[0024] While the present invention will be described in connection with
embodiments of a plastic split bushing for 3-4 inch metal conduits, it will be
readily apparent to one of ordinary skill in the art armed with the present
specification that the present invention can be modified and applied to any
suitable bushing, device, or the like with any suitable conduit or work piece
in
any suitable environment.
[0025] For context, a scenario wherein a prior art plastic split bushing is to
be
deployed is depicted in FIG. 1. As shown, a metal conduit 1 includes a
sidewall 2 defining a tube having a top edge 3 that poses a cutting threat to
a
bundle of wires 4 passing through the conduit 1. A plastic split bushing 5
includes a top channel 6 formed by a bend in a sidewall 7 extending from a
bottom outside edge 8. The sidewall 7 includes a slit 9 along its length.
[0026]As depicted the slit 9 is slanted instead of straight up and down the
sidewall. With this configuration, the slit 9 in the bushing 5 may be opened
by
a user pulling in opposite sides of the slit 9 in opposite directions against
the
normally closed bias of the plastic material. Once opened a sufficient amount,
the bushing 5 is maneuvered to accept the wires 4 in its interior and then
positioned to be mounted on the top edge 3 of the conduit 1 as shown in FIG.
1.
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[0027]The bushing 5 is pushed down until the top edge 3 of the conduit 1 is
seated in the channel 6 of the bushing 5. The right 10 and left 11 extensions
in the slit 9 area are pushed together to close the bushing 5. The bushing 5
now covers the entire circumferential edge of the conduit 1.
[0028] As will be appreciated, the prior art split bushing 5 is not locked
into
place absent the use of a separate closure to clamp the right 10 and left 11
extensions in a pinched, or closed, position. Depending on the conduit type,
the channel may be a loose of snug fit. Loose fitting bushings are susceptible
to being dislodged. As will also be appreciated, the prior art split bushing 5
is
limited in the amount the slit 9 can be spread open without concern of
breaking or over-stretching the plastic body.
[0029]As discussed herein below, a presently preferred embodiment
exemplifying aspects of the present invention provides improvements over
prior art bushings. As shown in FIGs. 2-10, a split bushing 100 in the form of
a unitary plastic casting comprises a body having a sidewall 20 including an
outside surface 21 and an inside surface 22. The inside surface may further
define threads 23 for receiving threaded conduits. The threads 23 may be full
threads for threaded conduits and connections, or "partial" threads that aid
the
tightening and securing of the bushing to a smooth conduit.
[0030]The sidewall continues from a bottom edge 24 through a top rim 30
and includes a longitudinal slit 25 or "split" that allows the bushing 100 to
be
opened to receive wires 4 passing through a conduit 1. The top rim 30
includes a top surface 31 and an inside surface 32 and is of a thickness
sufficient to define an inner channel 35 for receiving the outer edge 3 of a
conduit 1.
[0031]The bushing 100 includes a hinge 40 at an area directly opposite the
longitudinal slit 25. The longitudinal slit 25 in conjunction with the hinge
40
can be viewed as dividing the bushing 100 into a left arm 26 and a right arm
27 terminating at the hinge 40 with a left end 41 and a right end 42. The
hinge 40 is a "living hinge" comprising a thin area configured to allow the
left
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arm 26 and right arm 27 to be pulled in opposite directions to open the slit
25.
In the embodiment shown, the living hinge 40 is a thinned walled area having
an interiorly disposed triangular cutout. This configuration allows the hinge
to
be molded in the open (nearly 180 degrees or more) position so it can be
opened and closed without compromising the integrity of the material by over-
stretching the hinge area during closure. Alternatively, the bushing can be
molded in the closed position and the hinge configured to allow the arms to be
pulled apart without compromising the integrity or over-stretching the hinge
area during use.
[0032]As shown, the living hinge 40 is flanked by a left end 41 and a right
end
42 of the bushing 100. When rotated into the closed position, the left end 41
and right end 42 nest in a back clasp 45. Similarly, in the embodiment
depicted in the Figures, the left arm 26 and right arm 27 when rotated in the
closed position may nest in a front clasp 46. The clasps 45, 46 may be
configured as U-shaped channels for receiving the leading edges of the top
rim 30 at the meeting points 26, 27 and 41, 42.
[0033]The bushing 100 preferably includes an integrally formed locking
mechanism 50. In the depicted embodiment, the locking mechanism 50
includes a "zip tie" type lock. Specifically, the right arm 42 includes a male
tongue extension 51 and the left arm 41 includes a female catch body 55.
[0034]The catch 55 may be a channel defining an underpass through which
the tongue 51 is inserted. The tongue extension 51 includes raised ridges 52.
The ridges 52 are generally triangular and preferably include inclined leading
surfaces 53 and vertical back surfaces 54. With this configuration, the ridges
52 cam or deflect under the top of the underpass. Once a ridge 52 passes
through, the vertical surface 54 acts as a stop and prevents the tongue 51
from being retracted because it cannot slide under the underpass. The ridges
52 can only travel one-way through the channel catch 55 before being locked
from being retracted.
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[0035]The locking mechanism 50 provides the bushing 100 with the ability to
fit different types of conduits including EMT, IMC, Rigid, or PVC conduits ¨
including unthreaded and threaded types of each.
[0036]As shown in the Figures, and as will now be appreciated by one of
ordinary skill in the art armed with the present specification, the present
embodiment demonstrates the ability to use a single mold casting of a split
bushing that includes a living hinge and a locking mechanism to achieve the
various advantageous features realized by those aspects. Other
configurations are possible, including other locking mechanisms, other hinge
types, and other non-single mold casting configurations.
[0037]While advantageous embodiments have been chosen to illustrate the
invention, it will be understood by those skilled in the art that various
changes
and modifications may be made therein without departing from the scope of
the invention. The above embodiments are for illustrative purposes and are
not intended to limit the scope of the invention or the adaptation of the
features described herein to particular tools. Those skilled in the art will
also
appreciate that various adaptations and modifications of the above-described
preferred embodiments can be configured without departing from the scope
and spirit of the invention. Therefore, it is to be understood that the
invention
may be practiced other than as specifically described.
